". " syntax vs. "source "

Question

In my .bashrc file are these lines

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

I know that . <file> syntax is very popular...what is it doing exactly? How might this be different than running

source ~/.bash_aliases

Answer 1

In bash, . and source are equivalent. In other shells, though, they might be different. For example, traditional sh only supports ., not source.